Nonlinear Harmonic Electric Energy Metering System Based on the Wavelet Transform

Abstract

Background: To solve the problem of accurate measurement of nonlinear harmonic electric energy, a method for improving the harmonic electric energy measurement method based on the discrete wavelet packet decomposition and reconstruction algorithm is proposed. Objectives: Designs a reactive energy measurement method combined with Hilbert transformation, discusses the frequency characteristics of wavelet function, and points out that too high sampling rate will decrease in harmonic power measurement accuracy. By setting the discrete wavelet packet transformation decomposition, the stepping of the wavelet form brought by the excessively large wavelet packet decomposition scale is eliminated by the moncoband reconstruction algorithm. Methods: Experimental results show that the detection error obtained by numerical simulation using the wavelet transform algorithm is close to the standard instrument, with the maximum reference error within 0.013%~0.030%. Results and Conclusion: The feasibility and measurement accuracy of the nonlinear harmonic electric energy metering system are proved, providing an effective means for the accurate detection of the harmonic, interharmonic, and time-varying harmonic components of the electric power system.